G. Keller et C. Kopper, PERTURBATIVE RENORMALIZATION OF COMPOSITE-OPERATORS VIA FLOW EQUATIONS .2. SHORT DISTANCE EXPANSION, Communications in Mathematical Physics, 153(2), 1993, pp. 245-276
We give a rigorous and very detailed derivation of the short distance
expansion for a product of two arbitrary composite operators in the fr
amework of the perturbative Euclidean massive PHI4(4). The technically
almost trivial proof rests on an extension of the differential flow e
quation method to Green functions with bilocal insertions, for which w
e also establish a set of generalized Zimmermann identities and Lowens
tein rules.